1. All organisms are composed of 1 or more cells , and life process of metabolism and heredity occur within these cells 2. Cells are the smallest living things and and are the basic unit of organization in all living organisms 3. Cells arise only by division of pre existing cells

Chapter 6/7/8 - Cell Membranes Flashcards by Reginald S

Cell Theory

All organisms are composed of 1 or more cells , and life process of metabolism and heredity occur within these cells
Cells are the smallest living things and and are the basic unit of organization in all living organisms
Cells arise only by division of pre existing cells

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True or false

Life represents a continuous line of descendants from those early cells

True

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What is the reason why cell are small ?

Diffusion into and out the cell

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The small size of cells allow

Diffusion to occur easily

Lower energy expenditure

Lower waste

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Surface are to volume ratio

Volume increases rapidly as a cell increases in size

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1-10um in diameter

Prokaryotes

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10-100um in diameter

Eukaryotes

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How do we visualize cells

With use of technology (microscopes)

cells are not visible to the naked eye (resolution)

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What is the purpose of chemical stains

Chemical stains aid the resolution of cells, make them more visible through a microscope

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What are the 4 major components of a cell?

nucleoid or nucleus
cytoplasm
ribosomes (synthesize proteins)
plasma membrane

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Production of protein is achieved by

Ribosomes

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How many subunits make up a ribosome

Large subunit

Small subunit

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The area of a prokaryotic cell (simplest organism)

Nucleoid

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Eukaryotes (complex organisms) are contained in the

Nucleus

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The nucleus is surrounded by a double membrane called the

Nuclear envelope

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What is cytoplasm?

What does it contain?

Semi fluid matrix that fills the cells interior

Contains sugars, amino acids, proteins, and organelles used to carry out daily activities.

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Cytosol

The part of the cytoplasm that contains organic molecules and ions in solution

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Organelle

Specialized part of a cell, small cytoplasmic organ

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Separates the inside of the cell from the outside environment

plasma membrane

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Plasma membrane is composed of

Phospholipids and contains membrane proteins

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What is embedded in the plasma membrane

Proteins

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Phospholipid molecule make up the

Plasma membrane

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What is responsible for the cells ability to interact with the environment

Proteins of plasma membrane

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Lacks membrane bound nucleus, internal membrane system, and membrane bound organelles

Prokaryotes

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Prokaryotes are small simple cells surrounded by

Cell wall

True or false Prokaryotes have no compartments

True

Prokaryotes lack

Membrane bound organelles Lack cytoskeleton found in eukaryotes. But have elements of actin and tubulin to help maintain its structure

Prokaryotes have

Free floating ribosomes to synthesize proteins

Name two types of prokaryotes

Bacteria Archaea

Bacterial cell wall is composed of

Peptidoglycan , a sugar polymer

Functions of bacterial cell wall

Protect the cell Maintain its shape Prevent excess uptake or loss of water

Archaea Cell Wall is composed of various chemical compounds such as

Proteins Polysaccharides Inorganic compounds

Archaea Cell Membrane

A fatty acid chain (saturated hydrocarbon) that is covalently attached at both ends to glycerol, creating a monolayer rather than a bilayer

Can archaea adapt to changing environmental temperatures?

No. Unable to alter the degree of saturation of hydrocarbons

The cellular machinery that replicates DNA and synthesized proteins in archaea is more closely related to

Eukaryotic systems than bacterial systems

Long, threadlike structures protruding from the surface of a cell that are used for locomotion(movement)

Flagella

Prokaryotic Flagella

Protein fibers that extend out from the cell wall. (Rotary Motor)Movement powered by proton gradient There may be one or more per cell, or none depending on species.

Eukaryotic Cells

Contains an endomembrane system that allows the inside to be compartmentalized ---- this allows biochemical reactions to occur independently and simultaneously through organelles

Common organelles found in animal, fungi, and plant cells

``` Nucleus Nucleolus Ribosomes Cytoplasm Endoplasmic Reticulum(rough/smooth) Golgi Apparatus Lysosome Peroxisome Plasma Membrane Mitochondria Cytoskeleton (actin filaments, microtubules) ```

Largest organelle, spherical in shape, typically located in the center of a cell

Nucleus

The nucleus contains ______________ | Which are packaged DNA, or gene coding for protein

Chromosomes

All eukaryotic cells are supported by an internal protein scaffold called

Cytoskeleton

DNA are packed to form_____________ which are further packed by proteins to form_______________

Chromatins Chromosomes

Two phospholipid bilateral that surrounds the nucleus

Nuclear Envelope

Describe the nuclear envelope

One layer surrounds the nucleus The outer phospholipid bilayer forms the endoplasmic reticulum, or cytoplasm interior Membrane system

The outer phospholipid bilayer of the nuclear envelope forms the

Endoplasmic reticulum

Network of intermediate filament fibers that covers the inner surface of the nuclear envelope , which give the nucleus its shape Involved in the deconstruction and reconstruction of the nuclear envelope that accompanies cell division

Nucleus lamins

Found embedded between two phospholipid bilayers Scattered over the surface of the nuclear envelope

Nuclear pores

Nuclear pores allow

- Ion and small molecule exchange or diffuse between nucleus and cytoplasm - controlled transport of large proteins and RNA, RNA - protein complexes into and out of the nucleus

Nucleolus is found within

The nucleus

Houses ribosomal RNA genes, RNAs, and ribosomal proteins within itself during ribosome production

Nucleolus

Manufactures ribosomal RNA subunits (ribosomes) needed to synthesize protein

Nucleolus

Organelle within a cell that is important in synthesizing protein

Ribosome

Newly made protein is found in the

Cytoplasm

The large subunit and small subunit of ribosome is composed of a combination of RNA called

1. rRNA, or ribosomal RNA | 2. Proteins

Subunits of ribosome form only when

They are actively synthesizing proteins

Messenger RNA (mRNA)

Carries coding information from DNA

Transfer RNA (tRNA)

Carries amino acids

Ribosomes use the information in mRNA to direct the

Synthesis of protein

Ribosomes are found

Free in the cytoplasm Associated with internal membranes Embedded in the ER

Contains the message or protein sequence to be made

mRNA

Will read the mRNA and translate it into an amino acid chain

rRNA(ribosomes)

Will provide the amino acids to build the growing peptide chain

tRNA(ribosomes)

Factories that make proteins

Ribosomes

Cell interior contains an endomembrane system that

Divides the internal cell into compartments

What forms the largest endomembrane?

Endoplasmic reticulum

Exists as folded membranes, tubular networks, and other shapes

Endoplasmic reticulum

Phospholipid bilayer forms the

Endoplasmic reticulum

Cisternal Space/ lumen

Interior of ER

Two types of ER

Rough ER Smooth ER

Rough ER

Ribosomes embedded in membrane (hence, rough, bumpy appearance) Synthesizes proteins on the surface of ER(where ribosomes are located)

Fluid component of the cytoplasm containing dissolved organic molecules such as proteins and ions

Cytosol

What are the two largest compartments in eukaryotic cells

Cisternal space Cytosol

Proteins synthesized on the surface of the rough ER are destined to be exported from the cell to

Lysosomes or vacuoles Or Embedded in the plasma membrane

Where is the site for protein synthesis?

Rough ER

Determines wether the ribosome will become associated with the rough ER or remain a cytoplasmic ribosome

The sequence of proteins being synthesized

On the surface of the rough ER , synthesized proteins will enter the ____________ of the endoplasmic reticulum , where protein modification occurs

Lumen , cisternal space

Where are NEWLY SYNTHESIZED proteins modified by the addition of of Carbohydrates to form glycoproteins

Endoplasmic reticulum

How are newly synthesized proteins modified

By the addition of carbohydrates to form glycoproteins GLYCOPROTEINS - ( destined for secretion, are separated from other products and later packaged into vesicles that move to the Golgi for further modification and packaging for transport of other cellular locations)

What type of ER is this? 1) ribosome embedded on surface 2) synthesizes proteins 3) synthesized proteins enter lumen of ER, and are modified 4) proteins are sorted, further packages for the Golgi apparatus 5) proteins exported cytosol, lysosome, or vacuole, or embedded in plasma membrane

Rough ER

Regions of the ER with very few bound ribosomes

Smooth ER

Name structures of smooth ER

Tubules, flattened sacs, tubular arrays

Smooth ER membrane contains

Enzymes

Enzymes in the ER are involved in the synthesis of

Carbohydrates Lipids Steroid hormones

An important function of the smooth ER is to store

Intracellular Ca2+ - this keeps the cytoplasmic level low , allowing Ca2+ to be used as a signaling molecule

What is Ca2 + ?

A signaling molecule

What does Ca2+ trigger?

Muscle contraction Intracellular contraction

Where is Ca2+ stored

Smooth ER

What does the Smooth ER modify? Why?

Foreign substances to make them less toxic , detoxify harmful substances Ex: liver cells have large smooth endoplasmic reticulum —> neutralizes substances in the liver

Collection of flattened sac membranes

Golgi apparatus

Individual membrane sacs of the Golgi apparatus are called

Cisternae

1. Proteins and lipids manufactured on the rough and smooth ER are transported into the _____________ and modified as they go through it , 2. materials then bud off as secretory vesicles on the _____________

Golgi Apparatus Trans Face

Name three things the Golgi Apparatus does to molecules

Assembles Packages Distributes

cis face?

Front of Golgi

Trans face?

Back of Golgi

In plant cells, noncellulose polysaccharides that form part of the cell wall of plants/ are composed here and brought to the plasma membrane

Golgi Apparatus

Lysosome arise from

Golgi Apparatus

Lysosomes contain

High levels of degrading enzymes

What do degrading enzymes in lysosome do?

Catalyze the rapid break down of proteins, nucleic acids, lipids, and carbohydrates Degrades old cellular organelles(makes room for new organelles)

As phagocytosis (eats) wastes, a proton pump pushes H+ into the lysosome, decreasing the pH. Why is this significant?

Activates digestive enzymes in lysosome Leads to destruction of old organelle

Membrane enclosed vesicles that contain enzymes needed for metabolism

Microbodies

True or False Peroxisome is a microbody

True

Microbody which contains enzymes involved in the oxidation of fatty acids.

Peroxisome

Peroxisomes form from the __________________, which can ________________________

The cushion of ER vesicles - ER vesicles can uptake peroxisomal enzymes, grow, and divide

Hence peroxisome breaking down fatty acids through oxidation, the resulting byproduct is _______________. Peroxisome contains ______________ to further beak this down

Hydrogen peroxide Catalase (breaks down to water/hydrogen)

Tubular organelle About the size of bacterium Found in all eukaryotic cells

Mitochondria

What 2 membranes does mitochondria contain

Smooth outer membrane Inner folded membrane

What are the layers in the inner folded membrane called

Cristae

In mitochondria, What does cristae form

Matrix -inner membrane Intermembrane space - outer compartment

In the mitochondria, proteins are embedded on________________ which carries out______________ to create atp.

The inner membrane (matrix) Oxidative metabolism

Mitochondria is considered a cell within a cell because it has its own

DNA , which produce proteins

True or false Mitochondria can divide to form new mitochondria

true

Supports the cell shape Anchors organelles Allows proteins to be distributed throughout the cell Allows cell movement What am I?

Cytoskeleton

What is the cytoskeleton composed of?

Protein fibers Actin filaments Microtubules Intermediate filaments

Composed of 2 protein chains loosely twined together Exhibit polarity, has a + and - end. Concentrated in bundles below the plasma membrane, known as stress fibers Responsible for cellular movements such as crawling, "pinching" during cell division, formation of cellular extensions What am I?

Actin filament

Largest of the cytoskeleton elements Hollow tubes, each composed of a ring of 13 protofilaments (a- & ß- tubulin polymerize to form ring) Protofilaments line up side by side around core to form hallow tube, give it shape What am I?

Microtubule

Name 3 characteristics of microtubules?

Facilitate movement Organize the cytoplasm Responsible for moving materials within the cell

Formed from proteins such as vimentin, keratin, or neurofilaments Once formed does not break down Stability and shape of cell (protein->vimentin) Most durable element in cytoskeleton in animal cells What am I ?

Intermediate filament

Centrioles are found in

Animal cells Most Protists

In animal cells, what is found in pairs and at right angles to each other near nuclear membranes

Centrioles

Region surrounding centrioles is the space called

Centrosome

Surrounding the centrioles(pairs) in the centrosome is the

Pericentriolar material

Contains tubulin and materials needed to convert tubulin to microtubules

Pericentriolar material

Microtubule organizing center

Organizes microtubules during cell division

Centrosomes of plants and fungi lack

Centrioles ***Contain microtubule organizing center

Animal Cells: Extracellular matrix What two proteins are secreted? Where are the proteins secreted? What does it form?

Glycoproteins and proteoglycans Into the surrounding space Forms protective cushion around cell

Plant cells: Cell Wall

Protects and supports Primary wall produced in young cells

True or false Chloroplast is absent in animal cells

True

Plant cells contain a cell wall True or false

True

Animal cells lack cell wall. True or false

True

The extracellular matrix is composed of

Glycoproteins, collagen, and elastin

Sticky substance released by plant cells to adhere to adjacent cells

Middle lamella (within cell wall)

structure found in many plant cells, located between the primary cell wall and the plasma membrane. Deposited Inside primary wall of fully expanded cells Ex: - cell 1 (primary) - cell 2

Secondary cell wall

Plant cells have specialized membrane bound structures called

Vacuoles

Tonoplast

Membrane surrounding large central vacuole

Contains channels that are used to help the cell maintain it tonicity

Tonoplast

Plant cells: What do vacuoles store?

Water Sugars Ions Other molecules

Plant Cell: Vacuole helps to maintain plant cell _____________, which allows plant cell______________

Tonicity Growth

Plant Cell: Found in plant cells and any cell that uses the suns energy to carry out photosynthesis

Chloroplasts

Plant Cells: Allows cell to make their own food

Chloroplasts

Plant Cells: Outer and Inner membrane , larger than mitochondria

Chloroplasts

Plant Cells : Inside the inner membrane of chloroplasts are stacks of membranes called

Grana

Plant Cells: Chloroplasts What is grana composed of?

Several thylakoid disks

Plant Cell: Chloroplasts->Grana What does the surface of thylakiod disks contain?

Photosynthetic pigments , or chlorophyll

Plant Cell: chloroplasts-> grana-> thylakoids Fluid matrix that surrounds thylakoids and contains enzymes to synthesize glucose

Stroma

Plant Cells: Chloroplasts is considered a cell within a cell because it contains

DNA

Plant Cells: Chloroplasts and Mitochondria arose by

Endosymbiosis

Plant Cells: Theory that eukaryotic cell arose by symbiosis between two cell that were once separate Symbiosis def. - (interaction btw 2,beneficial for both)

Endosymbiosis

Cell Movements: Intracellular Transport of materials are performed along_________

Microtubules

Cell Movements: intracellular Requires 4 components which are?

Vesicles or organelle to be transported Motor protein that does the moving Connector molecule that holds the cargo Microtubule as the track

Cell Movements : Extracellular Why do actin filaments rearrange intracellularly

I'm to allow cells to crawl "Crawl cell" destroy pathogens

Cell Movements: Extracellular -> Crawl Cell Process 1. Actin filaments in leading cell quickly polymerize to ___________________ 2. Then, Microtubules polymerize to __________ 3. Lastly, actin in trailing end depolymerizes to _________________

1. To stretch cell forward 2. To stabilize the leading end 3. To contract the cell towards its body

Cell Movements: Extracellular Aids in propelling a cell Evolved early on in Eukaryotes Circular shape consisting of 9 microtubule pairs arranged in a ring structure and surrounds 2 central microtubules (9 + 2 structure) What am I?

Flagella

Cell Movements: Extracellular -> flagella What is it's motor protein? What does the motor protein cause?

Dynein Causes microtubules to move past each other in UP - DOWN WAVES

Cell Movements: Extracellular More modern and evolved form of flagella used in multi cellular eukaryotes Similar (9 +2) structure arrangement as flagella Arranged in rows & shorter than flagella

Cilia

Cell Movements: Extracellular What are functions of cilia?

Propels water Increases surface area Important in secretion and absorption

Wall layer deposited during the period of cell expansion

Primary wall

Cell Communication Cells need a way to communicate with each other (T/F) More specializations give rise to different populations of cells(T/F)

True True

Cell communication Set of genes that function to mark the surfaces of cells, identifying them as being a particular type

Surface Proteins (MHC)

Cell communication : Surface proteins Tissue specific cell surface maker On the surface of red blood cells Responsible for A, O, B blood types

Glycolipids

Cell Communication: surface proteins Found on virtually all cells in an organism that communicates "self" from anything that is "non-self". Ex: cells in immune system defend against invading cells What am I?

MHC proteins

Cell communication Name the various junctions

Gap Adhesive Communicating

Cell Communication Electrical signal driven by chemical means

Action potentials

Cell communication Identifying cell markers?

Surface proteins

Cell Communication Name all cell to cell connections

Adhesive junction Adherens junction Desmosomes

Cell Communication Name all Communicating junction

- gap junction | - plasmodesmata (plants)

Cell Communication Junction found in tissues subject to mechanical stress Attach cytoskeleton of a cell to cytoskeleton of of other cells or extracellular matrix Found in all animal species What am I?

Adhesive junction

Cell Communication Based on the protein cadherin (Ca2+) , which is a single transmembrane protein that protrudes into the extracellular space Can join with cadherin of adjacent cell

Adheren junction

Cell Communication Join adjacent cells via the cadherins DESMOCOLLIN & DESMOGLEIN , which interact with intermediate filaments of the cytoskeleton Unique to vertebrates Support tissue against mechanical stress What am I?

Desmosomes

Cell Communication Found in both invertebrates and vertebrates Forms a barrier to seal off a sheet of cells

Separate junction

Cell Communication Found in vertebrates Contains claudins (protein) Blocks substances from passing between cells Creates sheets of cells to prevent substances from crossing (nutrients absorbed from food must pass through sheet) Ex: stomach

Tight Junction

Cell Communication Allows diffusion of molecules between cells through small openings Permit small molecules or ions to pass from one cell to the other

Communicating junction

Cell Communication: communicating junction Direct communication channels between cells Found in invertebrates & vertebrates In invertebrates I AM formed by pannexins In vertebrates I AM formed by connexons I AM found in ANIMAL CELLS What am I ?

Gap Junction

Cell Communication: Pannexin/ connexon from two cells line up to form a

Gap junction

Cell Communication: Cytoplasmic connections that form across the touching plasma membranes A central tube that connects the Endoplasmic reticulum from 2 adjacent plant cells In plants, cell to cell junctions occur only at holes or gaps in walls What am I?

Plasmodesmata (in plants)

Chapter 6/7/8 - Cell Membranes Flashcards

(175 cards)